Engine starting power tool



Jan. 1, 1963 R. J. AsPEEK ENGINE STARTING POWER Toor.Y

Filed March 25, 1961 .WUJHNII 'United States This invention relates to a self contained power tool for driving the propeller and engine of a model airplane to initiate starting the engine.

Various devices have been employed heretofore to facilitate starting the miniature engines of model airplanes, however, the several devices of the prior art have not proven entirely satisfactory inasmuch as they are complicated in design and construction, expensive to manufacture, and difficult and unsatisfactory in use.

With the foregoing in view, the primary object of the invention is to provide a self contained power tool which is simple in design and construction, inexpensive to manufacture, and easy and highly satisfactory in use.

An object of the invention is to provide a rubber band ply driven power tool which is easy to manually wind to supply power in the tool and which has an automatic catch tang for holding the tool in the wound position.

An object of the invention is to provide a manual release for releasing the wound tool from the tang catch so as to impart rotation to an airplane propeller and engine attached thereto.

An object of the invention is to provide a frame having a rotatable shaft with a cross head having axially extending projections at one end thereof for engaging the propeller.

An object of the invention is to provide a catch tang which is bypassable in the winding direction and non-bypassable in the unwinding direction as automatically to hold 'the cross head from unwinding.

An object of the invention is to provide a lever adapted to engage a bearing on the shaft in contact with the cross head so that upon compressing the lever the lever moves the shaft and cross head axially outwardly past the tang so as to permit free rotation of the shaft and cross head.

An object of the invention is to provide axially extending pivotally mounted arms on the cross head so integrated as to drive a propeller and engine in the rubber band ply unwinding direction and so integrated that they can be over-run by the propeller upon the engine starting.

These and other objects of the invention will become apparent by reference to the following description of a power tool for driving or starting a model airplane engine embodying the invention taken in connection with the accompanying drawing in which:

FIG. 1 is a side elevational view ofthe power tool showing the cross head engaging the catch tang.

FlG. 2 is a View similar to PEG. l, showing the lever in the contracted position extending the cross head out of Contact with the catch tang so as to enable the cross head to freely rotate.

FIG. 3 is an end view of a portion of the device seen in FIG. 2 taken in the direction of the arrow 3 showing the pivotal mounting of the arms.

FIG. 4 is a bottom view, a portion of the device seen in FIG. 2 taken on the line 4--4 thereof showing the pivotal swing of the arms in dotted lines; and

FIG. 5 is a partial view of FlG. 1 taken on the line 5--5 thereof showing the angulation of the catch tang.

Referring now to the drawings wherein like numerals refer to like and corresponding parts through out the several views, the power tool disclosed therein to illustrate the invention comprises, a frame having' an intermediate spanning portion 11, an inwardly curved rear end 12, a reversely curved or U-shaped front end 13, and a projecting bevel tang catch portion 14 extending for- Patented Jan. 1, 1963 wardly of the frame. The shaft 15 is journalled in the reversed curved portion 13 and has an inner end terminating in an eye 16 which are anchored around the frame inwardly curving rear end 12. The cross head 18 is fixed on the shaft 15 and extends radially therefrom and terminates in outwardly axially projecting portions 19 and 20 which, hold the axially projecting arms 21 and 22 which are adapted to engage an airplane propeller.

The lever 23 is fulcrumed on the reverse curve portion 13 of the frame as at 24 and has a frontend 25' abutting the bearing 26 which is preferably freely disposed on the shaft 15; the lever is equipped with a rear end member 27 slidably connected with the frame rear end as at 28.

The cross head 18 is provided with reversely curved portions 30 and 31 on either side of the shaft 15 and the arms 21 and 22 have right angle portions 32 and 33 respectively pivotally disposed in the cross head reverse curved portions 30 and 31 with the arm portions 32 and 33 terminating in right angle portions 34 and 35 adapted to abut the cross head 18 in one pivotal direction and to avoid abutting the cross head 18 in the other pivotal direction as hereinafter more fully described.

To wind the rubber hand ply 17, the operator grasps one of the arms 21 or 22 and rotates the cross head 18 in a counterclockwise direction so that the inward pull of the rubber band ply 17 maintains the cross head 18 in contact with the tang 14 and due to the tangs angled or bevelled surface 40 the cross head rides there-across and past the engaging end 41 in the winding direction. However, in the unwinding direction the cross head engages the stop side 41 to prevent unwinding as seen in FIG. l. The user turns as many winds on the device as desired to store up the desired power.

The user then places the tool in the position seen in FIG. 2 relative to a model airplane propeller whereupon the arms 20 and 21 engage the propeller 15, and due to the winding direction of the band and the configuration of the arms 2li-22, angular portions 32-33, and abut- -ting portions 33-34, the arms are held in the axially projecting position of FIG. 2 with the ends 33 and 34 abutting the cross head 18 so as to hold the arms 21 and 22 against pivoting so as to transmit power therethrough to the propeller 50.

The user then draws the handle upwardly on the lever 23 whereupon the end 25 of the lever moves the bearing '26, shaft 15, and cross head 18 outwardly past the tang catch 41 whereupon the rubber band ply 17 drives the cross head and the arms 21 and 22 drive the propeller.

Upon the rubber band ply 17 running down and the propeller rotation starting the engine, not shown, the propeller 50 over-runs the arms 21 and 22 and the cross head 18, whereupon it contacts the arms 21 and 22 on the opposite sides and whereupon they are free to pivot as they are moving the abutting ends 33 and 34 away from the cross head 18 so that thereby the propeller 56 is adapted to over-run the arms 21 and 22. i

In operation the device is easily wound as the rubber band ply pulls inwardly on the shaft 15 and pulls the bearing against the lever end 25 throwing the lever outwardly as seen in FIG. l thereby placing the cross head 18 in the tang 4t) engaging position so that upon winding the cross head as previously described the catch tang 14 and stop engaging surface 41 automatically cornes into operation to hold the device in the wound position.

The user then extends the arms 711-22 to the position seen in FIG. 1 Iand places the arms relative to the propeller 50 as seen in FIG. 2; he then draws the lever 23 upwardly from the position seen in FIG. 1 to that of FG. 2 whereupon the lever end 25 moves outwardly moving the cross head 1S out of engagement with the tang stop 41 permitting the cross head to turn under the power of the rubber band ply 17.

It is to be noted that the rubber band ply 17 can be of any number of plural strands and power and due to the fact that the eye 16 is open and the frame end 12 exposed, it is obvious that any number of plies can be placed on the device or a number of plies removed as desired and this provides ready adaption of the tool to any size or power engine to be turned or cranked.

ln the preferred for-m of the device, the frame and other parts are made of strap metal and the reverse curve portions 13 provide a double bearing for the shaft 15 journalled therein and the free bearing 26 provides a stationary member for engaging the lever end and a smooth bearing for engaging the cross head 13 so as not to frictionally retard rotation of the cross head 1S.

While the lframe is shown with a reverse curve portion and the lever 23 is shown fulcrumed thereon, it is obvious that the invention is not limited thereto as different configurations can be used within the purview of the ind vention and the scope of the appended claims.

The inventive power tool with these features con stitutes a compact, durable and neat appearing mechanism which is easily operated to rapidly rotate a model airplane minature internal combustion engine and the preferred embodiment presents a very inexpensive tool well within the purchasing power of the buyer.

Although but a single embodiment of the invention has been shown and described in detail, it is obvious that many changes may be made in the size, shape, detail and arrangement of the various elements of the invention within the scope of the appended claims.

I claim:

1. A power tool particularly suitable for starting model airplane engines comprising a fra-me having an inwardly curved rear end, a spanning intermediate portion, and a reverse curved front portion; a hand lever fulcrumed on said front end reverse curved portion having a front end overlying said frame front end, an intermediate portion, and a rear end slidably disposed relative to said frame rear end, a shaft journalled in said frame front end and said lever front end having an inner end terminating in a rubber band receiving eye and an outer end; a rubber band plural ply disposed between said shaft eye and said frame inwardly curved rear end for driving said shaft, a cross head fixed on said shaft outer end, projections on said cross head extending axially 4for engaging an airplane propeller, a free bearing on said shaft between said cross head and said lever front end; and a bevelled tang adapted to bypass said cross head when being manually turned to wind said rubber band in the winding direction and to abut said cross head in the unwinding direction to prevent unwinding; said lever being adapted to move said cross head to rotate under the power of said rubber band unwinding.

2. In a device as set forth in claim 1, swing arms axially extending from said cross head projections adapted to drive against a propeller in the unwinding direction and to swing out of axial position in the unwinding direction when the propeller is driven by an engine and overruns said cross head.

3. A power tool particularly suitable for starting model airplane engines comprising a frame having rear end, a spanning intermediate portion, and a front portion; a hand lever fulcrumed on said frame front end having a front end overlying said frame front end, an intermediate portion, and a rear end; a shaft journalled in said frame front end and said lever front end having an inner end terminating in a rubber band receiving eye and an outer end; a rubber band plural ply disposed between said shaft eye and said frame rear end for driving said shaft, la cross head xed on said shaft outer end, projections on said cross head extending axially for engaging an airplane propeller, a bearing on said shaft between said cross head and said lever front end; and a bevelled tang adapted to bypass said cross head when being manually turned to wind said rubber band iu the winding direction and to abut said cross head in the unwinding direction to prevent unwinding; said lever being adapted to move said bearing and shaft axially outwardly to move said cross head axially outwardly so as to bypass said tang to permit said cross head to rotate under the power of said rubber band unwinding.

4. In a device as set forth in claim 3, swing arms axially extending from said cross head projections adapted to drive against a propeller in the unwinding direction and to swing out of axial position in the unwinding direction when the propeller is driven by an engine and overruns said cross head.

5. A power tool particularly suitable for starting model airplane engines comprising a frame having rear end, a spanning intermediate portion, and a front portion; a hand lever fulcrumed on said frame front end having an end overlying said frame front end and an intermediate portion; a shaft journalled in said frame front end and extending past said lever front end having an inner end terminating in a rubber band receiving eye and an outer end; a rubber band plural ply disposed between said shaft eye and said frame rear end for driving said shaft, a lcross head iixed on said shaft outer end, projections on said cross head extending axially for engaging an airplane propeller; and a bevelled tang adapted to bypass said cross head when being manually turned to wind said rubber band in the winding direction and to abut said cross head in the unwinding direction to prevent unwinding; said lever being adapted to move said shaft axially outwardly to move said cross head axially outwardly so as to bypass said tang to permit said cross head to rotate under the power of said ru-bber band unwinding.

6. 1n a device as set forth in claim 5, swing arms axially extending from said cross head projections adapted to drive against a propeller in the unwinding direction and to swing out of axial position in the unwinding direction when the propeller is driven by an engine and overruns said cross head.

7. A power tool particularly suitable for rapidly rotating the propeller and internal combustion engine of model airplanes to crank the engine to initiate starting, comprising, a frame having opposite front and rear ends, a shaft rotatably journalled in said frame front end; said shaft having an outer end projecting beyond said frame front end and an inner end within said frame; said shaft inner end including a rubber band plyv receiving eye; a rubber band ply having opposite ends disposed between said shaft eye and said frame rear end so as to be rotatable `with said shaft at one end of said rubber band ply and stationary with said frame at the opposite end of said rubber band ply; a cross head fixed on said shaft outer end having radial ends, projections on said cross head radial ends extending axially outwardly beyond said frame, shaft, and cross head for engaging a propeller mounted on an engine; said cross head and projections being manually rotatable in a direction opposite to the direction of rotation of the engine to wind said rubber band; releasable holding means for holding said cross head against turning under the power of said band so wound, and manual release means for releasing said holding means to permit said rubber band so wound to rotate said cross head to rotate an engine attached to a propeller to start Same.

References Cited in the file of this patent UNITED STATES PATENTS 2,622,701 Kellogg et al Dec. 23, 1952 FOREIGN PATENTS 313,265 Germany July l1, 1919 1,016,169 Germany Sept. 19, 1957 

1. A POWER TOOL PARTICULARLY SUITABLE FOR STARTING MODEL AIRPLANE ENGINES COMPRISING A FRAME HAVING AN INWARDLY CURVED REAR END, A SPANNING INTERMEDIATE PORTION, AND A REVERSE CURVED FRONT PORTION; A HAND LEVER FULCRUMED ON SAID FRONT END REVERSE CURVED PORTION HAVING A FRONT END OVERLYING SAID FRAME FRONT END, AN INTERMEDIATE PORTION, AND A REAR END SLIDABLY DISPOSED RELATIVE TO SAID FRAME REAR END, A SHAFT JOURNALLED IN SAID FRAME FRONT END AND SAID LEVER FRONT END HAVING AN INNER END TERMINATING IN A RUBBER BAND RECEIVING EYE AND AN OUTER END; A RUBBER BAND PLURAL PLY DISPOSED BETWEEN SAID SHAFT EYE AND SAID FRAME INWARDLY CURVED REAR END FOR DRIVING SAID SHAFT, A CROSS HEAD FIXED ON SAID SHAFT OUTER END, PROJECTIONS ON SAID CROSS HEAD EXTENDING AXIALLY FOR ENGAGING AN AIRPLANE PROPELLER, A FREE BEARING ON SAID SHAFT BETWEEN SAID CROSS HEAD AND SAID LEVER FRONT END; AND A BEVELLED TANG ADAPTED TO BYPASS SAID CROSS HEAD WHEN BEING MANUALLY TURNED TO WIND SAID RUBBER BAND IN THE WINDING DIRECTION AND TO ABUT SAID CROSS HEAD IN THE UNWINDING DIRECTION TO PREVENT UNWINDING; SAID LEVER BEING ADAPTED TO MOVE SAID CROSS HEAD TO ROTATE UNDER THE POWER OF SAID RUBBER BAND UNWINDING. 